据1991年5月《高速柴油机和传动装置》杂志报道,英国里卡多公司最近与北欧完成了天然气公共汽车合作项目,其中 Scania 天然气六缸发动机达到了极低的排放水平。该火花点火式发动机拟用于市区公共汽车。该项目的成果表明,该机排放水平低于美国联邦重型发动机瞬态试验循环规定的指标。 According to a report in May 1991 “High Speed ​​Diesel Engines and Drives,” British company Ricardo recently completed a natural gas bus co-operation with Northern Europe, of which the Scania natural gas six-cylinder engine achieved very low levels of emissions. The spark ignition engine is intended for urban buses. The project’s results show that the aircraft emission levels below the United States Federal Heavy Engine transient test cycle of the indicators.